This invention generally relates to the preparation of waste materials contining water as solutions or slurries for effective disposal thereof. The invention particularly relates to the disposal of water-containing radioactive waste materials from nuclear power plants, and provides for their volume reduction and safe storage or burial.
Light water moderated and cooled nuclear power plants require extensive water treatment facilities to maintain the water within prescribed radioactivity and purity levels. Corrosion products entrained within the water become activated during their passage through the reactor core and some fission products leak out of the fuel bundles into the water. The treatment processes for purifying such water produce effluents of ion exchange regeneration solutions which commonly comprise solutions of sodium sulfate, filter sludges combined with either ion exchange or other filter-aid materials, and waste ion exchange resins that are all somewhat radioactive. These wastes require encapsulation to minimize groundwater leaching and burial for final disposal.
Heretofore, these wastes have been mixed with concrete, asphalt, or urea-formaldehyde as encapsulation media. However, these processes do not provide a significant volume reduction, and indeed in the case of concrete encapsulation, the volume increases. Burial and transportation costs have escalated appreciably in recent years which make burial volume and hence waste volume reduction of paramount economic importance. Leachability of radioactive materials from the buried waste into the ground water has also become a very sensitive issue. None of the above encapsulating materials provide a low enough leach rate, over a long-term period, to avoid problems in this area.
Other disposal techniques are discussed in U.S. Pat. No. 4,077,901 where the readioactive waste solutions, or slurries, are dispersed within a polymerizable agent which forms a solid polymer about the waste for disposal. Also, U.S. Pat. No. 4,119,560 discusses dehydrating the wastes with a heated inert carrier with ultimate encapsulation of the dried waste in a polymerized epoxy for disposal.